Nebulizing device



y 7, 1964 v F. c. MOORE ETAL 3,140,051

7 NEBULIZING DEVICE Filed Dec. 20. 1962 2 Sheets-Sheet 1 y 7, 1964 F. c. MOORE ETAL 3,140,051

NEBULIZING DEVICE Filed Dec. 20. 1962 2 Sheets-Sheet 2 jyi HHH

United States Patent 3,140,051 NEBULIZING DEVICE Francis C. Moore and Marvin W. Nicely, Indianapolis,

Ind., assignors to American Hospital Supply Corporation, Evanston, 111., a corporation of Illinois Filed Dec. 20, 1962, Ser. No. 246,190 7 Claims. (Cl. 239215) This invention relates to a nebulizer, and more specifically, to a device for producing a fog or cloud of small micron-sized particles of a liquid suspended in a gas.

In our copending application, Serial No. 144,779, filed October 12, 1961, now US. Patent No. 3,077,307, we disclose a nebulizer which requires a source of gas under pressure for its operation, and it is the forced flow of such gas through the unit which results in aspiration of liquid from the units reservoir and which causes the discharge of a liquid-gas spray from the nozzles or jets. The drawings of such copending application do not illustrate means for compressing the gas supplied to the unit, but it is apparent that any suitable compressor might be connected to the nebulizer to produce a completely operative combination. It is to be noted, however, that the addition of a compressor, along with driving means to operate it, would necessarily and significantly increase the bulk of the entire operating unit.

rate and, in most instances, is hand operated. For ex' ample, it has been customary to provide a hand operated bulb member for creating the air pressure necessary to draw fluid from the reservoir and force it in a spray from the jets.

Accordingly, it is a principal object of the present invention to provide a nebulizer of compact construction havin g self-contained means for forcing gas and liquid through the flow passages thereof to the spray nozzles. Another object is to provide a nebulizer capable of continuous operation without the need for an outside source of compressed air and without the need for an external compressor, motor, or other attachments.

Another object of this invention is to provide a nebulizer having nozzles arranged to create high velocity streams of nebulized material and to direct those streams to form a vortex within the chamber of the apparatus. In this connection, it is a specific object to provide a nebulizer which utilizes centrifugal force in extracting larger droplets from the nebulized streams of liquid.

Another object is to provide a nebulizer in which centrifugal force is utilized to draw fluid from a reservoir and discharge it through a plurality of jet openings. A further object is to provide such a nebulizing apparatus with means adjacent the jet openings for decreasing droplet size and for greatly increasing the number of droplets or liquid particles.

A still further object is to provide a nebulizer having rapidly rotating intake means and having anti-cavitation elements to prevent interruption in the intake or liquid. An additional object is to provide a nebulizer having means which performs the dual functions of preventing cavitation and of extracting larger droplets or particles from discharged air-gas streams.

Other objects will appear from the specification and drawings in which:

FIGURE 1 is a side elevational view of a nebulizer embodying the present invention;

FIGURE 2 is a top plan view of the nebulizer;

FIGURE 3 is a top plan View of the nebulizer casing,

ice

the cover, motor and jet assembly being withdrawn therefrom;

FIGURE 4 is a vertical sectional view taken along line 4-4 of FIGURE 2;

FIGURE 5 is an enlarged horizontal sectional view of the jet assembly taken along line 55 of FIGURE 4;

FIGURE 6 is an enlarged sectional view similar to FIGURE 5 but illustrating a modification of the jet assembly;

FIGURE 7 is an enlarged broken perspective view illustrating one of the jet tubes of the modified construc tion illustrated in FIGURE 6;

FIGURE 8 is an enlarged perspective view illustrating a third form of jet tube;

FIGURE 9 is a sectional view of the jet tube construction illustrated in FIGURE 8;

FIGURE 10 is an elevational view in reduced scale and partly in section, showing an alternative form of nebulizer casing.

In the embodiment of the invention illustrated in FIG- URES 1 through 5, the numeral 10 generally designates a nebulizer apparatus having a generally cylindrical casing 11, driving means'in the form of an electric motor 12, and a fluid intake and jet assembly 13. In the particular illustration given, the casing is shown as being formed from a transparent plastic material although it is to be understood that opaque materials as well as materials other than plastics might be used.

The casing is provided with a lower section 14 defined by cylindrical side wall 15 and bottom wall 16, and an upper section or cover 17 supported upon the lower section and secured thereto by screws 18 or by any other suitable connecting means.

Motor 12 is centrally disposed within the chamber 19 of the casing and is suspended within a cylindrical sleeve 20 by means of mounting bars 21. The vertically elongated sleeve is coaxial with the casing and with the shaft 22 of the motor and is preferably closed at its lower end to protect the motor incased therein. The motor shaft projects downwardly through the centrally apertured end wall 23 of the sleeve and a suitable sealing ring 24 prevents the upward flow of liquid into the motor compartment 25.

As shown most clearly in FIGURES 4 and 2, cover 17 is provided with a discharge opening 26 adjacent the periphery thereof. A suitable discharge tube 27, which permits the connection of a hose extension to the discharge opening, may be fitted and secured within the opening as shown in FIGURE 4.

Projecting downwardly from a series of circumferentially-spaced openings 28 in the cover are a plurality of air intake tubes 29. As shown in FIGURE 4, each tube extends downwardly alongside sleeve 20. The upper and lower ends of the air intake tubes are open so that air may be drawn into the chamber 19 during operation of the apparatus, as will be described shortly.

The jet tube assembly 13 essentially comprises a liquid intake tube 30 coaxial with motor shaft 22 and communicating through a manifold 31 with a plurality of jet tubes 32. All of the jet tubes extend along a plane generally perpendicular to the rotational axis of liquid intake tube 30 but are canted rearwardly with respect to lines extending radially from the coaxial shaft 22, tube 30 and manifold 31. The angle of radial deviation, designated by the letter x in FIGURE 5, may vary considerably, depending upon the revolution rate of the motor, the dimensions of the parts, and the particular liquid to be nebulized. Angles within the range of approximately 10 to 60 degrees have been found effective, and angles within the range of 1-5 to 25 degrees are preferred. While the jet tubes illustrated in the drawings are straight,

J it may be desirable to provide curved tubes and, in that event, the angular measurements should be taken at the free ends of the tubes.

The manifold 31 is secured at its upper end to connector 3,3 which is in turn secured to the lower end of motor shaft 22. Thus, upon operation of the motor, the connector 33, manifold 31 and liquid intake tube 30 all rotate about the axis of the shaft and in the direction indicated by arrow 34 (FIGURE The jet tubes are all angled in the same reverse direction with respect to the direction of rotation of the unit.

Referring to FIGURE 4, it will be noted that the lower end of the liquid intake tube terminates just above the bottom wall 16 of the nebulizer casing. Radiating outwardly from the center of the bottom wall are a plurality of circumferentially-spaced baffles 35. Each baflle is provided with bottom and outer edges in contact with the inner surfaces of the casings bottom and side walls and is also provided with a generally arcuate inner edge 36. It will be observed that the baffles extend above as well as below the normal level of the liquid within the casing, such level being indicated by the broken line 37 in FIGURE 4. Specifically, the tapered upper end portions of the baffles project well above the level of jet tubes 32 so that fluid sprayed from the jets will necessarily impinge upon the radially-extending baffles.

An additional bafiie plate 38 may be provided within the casing adjacent discharge opening 26 and discharge tube 27, as illustrated in FIGURES l and 2. Baflle plate 38 extends vertically from the undersurface of the cover to a point spaced well above baffles 35, and is located behind the discharge opening in the terms of the direction of rotation of the jet tube assembly and the spiral flow of nebulized material within the casing.

In the operation of the structure so far described, water or any other suitable liquid is introduced into the casing through discharge tube 27 (which also acts as a filler tube) until the liquid reaches the level indicated by numeral 37. When motor 12 is turned on, rapid rotation of the jet tube assembly causes a decrease in pressure within manifold 31 and intake tube 30. Liquid is drawn upwardly into the tube and manifold, and is forceably discharged from the jet tubes because of the centrifugal forces developed by the assemblys rapid rotation. As the liquid is sprayed outwardly from the passages of the jet tubes, the droplets collide with the side wall of the casing and with the upper end portions of baflles 35, thereby breaking into droplets or particles of smaller size. The small droplets tend to circulate upwardly in a spiral path within the chamber 19, creating a vortex of nebulized particles. All but the smallest of these particles impinge on the cylindrical inside surface of the casing, such surface thereby acting as a secondary baffle in the centrifugal extraction of oversized particles or droplets. Liquid collected by the casings side wall drains downwardly into the reservoir so that only the fine droplets or particles of a size smaller than microns pass upwardly through the discharge tube 27. As previously described, the baffle or deflector plate 38 assists in directing the micron-sized particles and vapor into the discharge opening and tube.

In addition to breaking up larger droplets discharged from the jet tubes, the radially extending baifles 35 perform an important function as anticavitation elements. In other words, the baflles restrain the circumferential flow of liquid and the resultant formation of a vortex in the liquid body. The lower end of the liquid intake tube 30 therefore remains submerged within the body of liquid as long as the level is above the tubes lower end when the unit is not in operation. If desired, the nebulizer may be provided with any automatic fluid level control device for maintaining a substantially uniform liquid level within the chamber.

The embodiment illustrated in FIGURES 6 and 7 is identical in every respect to the structure already described except that the jet tubes 32 are provided with air intake branches 39. Each branch tube is disposed near the free end of one of the jet tubes and angles inwardly with respect to that tube. While various angles may be used, it is necessary that the angle Y represented in FIGURE 6 be no greater than 90 degrees. Angles with in the range of 10 to degrees have been found effective, and angles within the range of 20 to 45 degrees are preferred.

In the operation of the modified structure, the outward flow of liquid under the influence of centrifugal force, as indicated by arrow 40 in FIGURE 7, aspirates air through branch tube 39, as indicated by arrow 41, with the result that air and liquid are intermixed prior to discharge from the free end of the jet tube. The result is in an increase in the number of droplets, and a decrease in droplet size, in comparison with the action of the jet tube assembly of the first embodiment. In other respects, the operation of the two embodiments is identical.

FIGURES 8 and 9 illustrate another modification of the jet tube construction. In this construction, the end portion of each jet tube is turned rearwardly in a direction opposite to the direction of rotation of the assembly, as represented by arrow 34". Preferably, the free end portion of the jet tube extends tangentially or nearly tangentially, with respect to the circle defined by that portion as the jet tube assembly rotates. A frustoconical shaped sleeve 42 is secured to the end of the jet tube by radial mounting elements 43, although any other suitable mounting means which does not significantly obstruct the passage of air through the sleeve may be used.

The smaller end of the sleeve is disposed at the extreme end of the jet tube and has a suificiently larger internal diameter than the outer diameter of the tube to define an annular orifice 44.

Upon rotation of the jet tube assembly, air is scooped by the enlarged ends of sleeves 42 and is compressed as it flows rearwardly into and through the sleeves in the direction represented by arrows 45. The air is released through the constricted discharge orifice 44 at the same point of discharge of liquid flowing through the jet tube and the expansion of the air, along with the turbulence produced thereby, acts upon the liquid discharged from the jet tube to decrease droplet size and increase the number of such droplets.

Like the embodiment of FIGURES 6 and 7, the modified construction of FIGURES 8 and 9 is otherwise identical instructure and operation with the embodiment represented in FIGURES 1 through 5.

FIGURE 10 illustrates an alternative form of casing which may be used with any of the jet tube constructions mentioned above. Casing 11' is spherical in shape, having a dome-shaped upper section or cover 17' and a bowl-shaped lower reservoir section 14'. The lower section is provided with a cylindrical base portion 46 which accommodates jet tube assembly 13 and which is adapted to contain a quantity of liquid, the level of the liquid being indicated at 37.

The two sections are securely connected along the casings horizontal mid plane and a gasket 47 is clamped between the flanges of the upper and lower sections. This annular gasket projects inwardly into chamber 19' and serves as a baflle for extracting larger droplets from nebulized material discharged from the jet tube assembly. As in the previous embodiment, a plurality of anti-cavitation baffles 35 are provided in the lower reservoir section and project above the level of the liquid and above the plane of discharge tubes of the jet tube assembly.

In the operation of the structure shown in FIGURE 10, the radial elements 35' act as primary baflles in reducing the size of the droplets discharged from the jet tubes. As the mist of nebulized material swirls upwardly within the chamber 19', intermediate sized droplets impinge on the inner surface of the lower section 14' and upon the gasket or secondary bafile 4'7. Droplets which are too small to be caught by the gasket but which are still larger than about microns in size tend to contact the inner surface of the dome-shaped upper section as the vortex of nebulized material increases in its angular velocity. Thus, before the swirling mist is discharged through outlet tube 27', particles or droplets larger than about 10 microns in size are centrifugally extracted and are returned to the reservoir.

While in the foregoing, we have disclosed several embodiments of the invention in considerable detail for purposes of illustration, it will be understood by those skilled in the art that many of these details may be varied without departing from the spirit and scope of the invention.

We claim:

1. A nebulizer apparatus comprising a casing forming a liquid reservoir therein, a jet tube assembly disposed within said casing and comprising a vertical intake tube and a plurality of jet tubes communicating with and extending outwardly adjacent the upper end of said intake tube, said intake tube being positioned and arranged with its lower end adapted to be submerged in a body of liquid contained Within said reservoir, each of said jet tubes being branched adjacent the free end thereof to provide an inwardly and rearwardly directed air-intake port, power driving means operatively associated with said assembly for rotating the same about the axis of said intake tube and a plurality of baffles provided by said casing and extending radially and above the level of said jet tubes, whereby, water droplets discharged from said jet tubes impinge directly on said bafiles and are nebulized thereby.

2. The structure of claim 1 in which said casing is generally of spherical shape.

3. A nebulizer apparatus comprising a casing having a liquid reservoir therein and having a discharge opening in the top thereof, a jet tube assembly disposed within said casing adjacent the lower end thereof and being mounted for rotation about a vertical axis, said assembly including an intake tube extending along said vertical axis and a plurality of horizontally extending jet tubes having their inner ends converging about said axis and communicating with said intake tube, and a motor operatively connected to said assembly for rotating the same within the lower portion of said casing, said casing providing a horizontally curved surface concentric with the rotational axis of said assembly, said casing also being provided in its lower portion with a plurality of radially-extending anti-cavitation bafile plates, each of said baflle plates having an outer portion extending above the level of said jet tubes and being tapered downwardly and inwardly along the bottom of said casing, whereby, water droplets discharged from said jet tubes impinge directly against said bafile plates and are nebulized thereby.

4. The structure of claim 3 in which said inner surface is also curved vertically, said casing being generally spherical in shape.

5. A nebulizer apparatus comprising a casing providing a liquid reservoir therein and having a discharge opening in the top thereof, a jet tube assembly disposed within said casing for rotation about a vertical axis, said assembly comprising a vertical intake tube extending along said axis and a plurality of jet tubes extending along a generally horizontal plane, said jet tubes having their inner ends converging about said vertical axis and communicating with the upper end of said intake tube, a motor connected to said assembly for rotating the same about said vertical axis, each of said jet tubes being branched adjacent the free end thereof to provide an air intake tube extending inwardly and rearwardly and communicating with said jet tube adjacent the free end thereof.

6. The structure of claim 12 in which each of said jet tubes is angled rearwardly with respect to radius lines emanating from the rotational axis of said assembly.

7. The structure of claim 5 in which said casing is provided with a side wall having a horizontally curved inner surface coaxial with said jet tube assembly, said wall providing a plurality of radially-extending baffle plates positioned for direct impingement by water droplets discharged from said jet tubes.

References Cited in the file of this patent UNITED STATES PATENTS 2,437,103 Leach Mar. 2, 1948 3,005,591 Bradley Oct. 24, 1961 3,108,147 Flury Oct. 22, 1963 FOREIGN PATENTS 310,622 Great Britain May 2, 1929 469,854 Great Britain Aug. 4, 1937 1,034,842 France Apr. 15, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3 l4O O5l July 7 1964 Francis C, Moore et alo It is hereby certified, that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 6 line 29, for the claim reference numeral "'12" read 5 Signed and sealed this 24th day of November 1964.,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J BRENNER} Attesting Officer 5 I Commissioner of Patents 

3. A NEBULIZER APPARATUS COMPRISING A CASING HAVING A LIQUID RESERVOIR THEREIN AND HAVING A DISCHARGE OPENING IN THE TOP THEREOF, A JET TUBE ASSEMBLY DISPOSED WITHIN SAID CASING ADJACENT THE LOWER END THEREOF AND BEING MOUNTED FOR ROTATION ABOUT A VERTICAL AXIS, SAID ASSEMBLY INCLUDING AN INTAKE TUBE EXTENDING ALONG SAID VERTICAL AXIS AND A PLURALITY OF HORIZONTALLY EXTENDING JET TUBES HAVING THEIR INNER ENDS CONVERGING ABOUT SAID AXIS AND COMMUNICATING WITH SAID INTAKE TUBE, AND A MOTOR OPERATIVELY CONNECTED TO SAID ASSEMBLY FOR ROTATING THE SAME WITHIN THE LOWER PORTION OF SAID CASING, SAID CASING PROVIDING A HORIZONTALLY CURVED SURFACE CONCENTRIC 